Photolysis of beta-blockers in environmental waters

Many drugs such as beta-blockers have been shown to occur in aquatic environments. Even if adequate ecotoxicity data are not available, it is of primary importance to get informations about their fate in environmental waters, particularly about their photofate in sewage treatment plant effluents (STP). The main difficulties when studying pharmaceutical photochemical behaviour in environmental waters, are linked to the very low environmentally relevant concentrations (ng L(-1) to microg L(-1)) which can generate problems in terms of analytical sensitivity. Moreover, the complexity of environmental matrices can modify micropollutants degradation kinetics. The photodegradation of beta-blockers has been compared at two concentration levels (10 microg L(-1) and 10 mg L(-1)) and in two different matrices (pure water and STP effluent). It has been shown that the concentration does not influence beta-blockers degradation pathways, thus allowing the identification of degradation compounds using the 10 mg L(-1) solutions. Although environmental waters speed up the degradation process, the same photoproducts were appeared in both matrices. Using LC-MS/MS, hydroxyl radical additions have been identified as an important degradation pathway for especially pindolol, propranolol and timolol, leading to several positional isomers, corresponding to mono-, di- or tri-hydroxylations. Kinetics of appearance/disappearance of these photoproducts have been studied in STP effluents.     

Transformation kinetics of 6-methoxybenzoxazolin-2-one in soil

Wheat (Triticum aestivum L.) and other cereals produce allelochemicals as natural defense compounds against weeds, fungi, insects and soil-borne diseases. The main benzoxazinoid allelochemical of wheat is 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), bound as beta-glucoside and released upon plant injury. When leached from wheat to soil, DIMBOA is microbially transformed to 6-methoxy-benzoxazolin-2-one (MBOA). Exploiting benzoxazinoids and their degradation products as substitutes for synthetic pesticides depends on knowledge of transformation pathways and kinetics. In an MBOA degradation experiment at a concentration of 2400 nmol g(-1) soil, the previously identified transformation products 2-amino-7-methoxy-phenoxazin-3-one (AMPO) and 2-acetylamino-7-methoxy-phenoxazin-3-one (AAMPO) were quantified. Three different kinetic models were applied to MBOA transformation kinetics; single first-order (SFO), first-order multi-compartment, and double first-order in parallel. SFO proved to be adequate and was subsequently applied to the transformations of MBOA, AMPO and AAMPO. Degradation endpoints, expressed as degradation time (DT), were calculated for MBOA, AMPO and AAMPO to test whether the maximum values for synthetic pesticides set by the European Commission and the Danish Environmental Protection Agency were exceeded. DT(50) values for MBOA and AMPO were 5.4 d and 321.5 d, respectively, and DT(90) values were 18.1 d and 1068 d, respectively. The DT(50) value for AMPO exceeded the maximum value. The persistence, concentrations and toxicity of metabolites such as AMPO should be considered when breeding cereal crops with increased levels of benzoxazinoids.     

Hot filter/impinger and dilution sampling for fine particulate matter characterization from ferrous metal casting processes

A study using two stack-sampling methodologies for collecting particulate matter (PM) emissions was conducted using a hot filter followed by a cold impinger sampling train and a dilution sampler. Samples were collected from ferrous iron metal casting processes that included pouring molten iron into a sand mold containing an organic binder, metal cooling, removal of the sand from the cooled casting (shakeout), and postshakeout cooling. The shakeout process contributed more to PM emissions than the metal pouring and cooling processes. Particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass emissions for the entire casting cycle ranged from 3.4 to 4.7 lb/t of metal for the hot filter/impinger method and from 0.8 to 1.8 lb/t of metal for the dilution method. Most of the difference was due to PM captured by the impingers, much of which was probably dissolved gases rather than condensable vapors. Of the PM fraction captured by the impingers, 96-98% was organic in nature. The impinger PM fraction contributed 32-38% to the total suspended particle mass and caused a factor of 2-4 positive bias for PM2.5 emissions. For the pouring and cooling processes only, the factor increased to over seven times.     

Air quality impacts of distributed energy resources implemented in the northeastern United States

Emissions from the potential installation of distributed energy resources (DER) in the place of current utility-scale power generators have been introduced into an emissions inventory of the northeastern United States. A methodology for predicting future market penetration of DER that considers economics and emission factors was used to estimate the most likely implementation of DER. The methodology results in spatially and temporally resolved emission profiles of criteria pollutants that are subsequently introduced into a detailed atmospheric chemistry and transport model of the region. The DER technology determined by the methodology includes 62% reciprocating engines, 34% gas turbines, and 4% fuel cells and other emerging technologies. The introduction of DER leads to retirement of 2625 MW of existing power plants for which emissions are removed from the inventory. The air quality model predicts maximum differences in air pollutant concentrations that are located downwind from the central power plants that were removed from the domain. Maximum decreases in hourly peak ozone concentrations due to DER use are 10 ppb and are located over the state of New Jersey. Maximum decreases in 24-hr average fine particulate matter (PM2.5) concentrations reach 3 microg/m3 and are located off the coast of New Jersey and New York. The main contribution to decreased PM2.5 is the reduction of sulfate levels due to significant reductions in direct emissions of sulfur oxides (SO(x)) from the DER compared with the central power plants removed. The scenario presented here represents an accelerated DER penetration case with aggressive emission reductions due to removal of highly emitting power plants. Such scenario provides an upper bound for air quality benefits of DER implementation scenarios.     

The influence of maize residues on the mobility and binding of benazolin: investigating physically extracted soil fractions

The amount of non-extractable residues and the distribution of benazolin and its metabolites were evaluated three months after herbicide application (14C-labelled) in physically extracted soil fractions of topsoil layers of undisturbed soil columns with and without incorporated maize straw (14C-labelled). In addition, a variety of wet-chemical and spectroscopic methods were used to characterise the structure of organic carbon within the different soil fractions. The addition of crop residues increased the amount of dissolved organic carbon, enhanced the aromaticity of the organic carbon structure and enforced the aggregation of organomineral complexes. After incorporation of crop residues, an increase in the formation of metabolic compounds of benazolin and of non-extractable residues was detected. These results indicate that the addition of crop residues leads to a decrease in mobility and bioaccessibility of benazolin and its metabolites.     

Life cycle assessment of the waste hierarchy--a Danish case study on waste paper

The waste hierarchy is being widely discussed these days, not only by cost-benefit analysts, but a growing number of life cycle assessments (LCA) have also begun to question it. In this article, we investigate the handling of waste paper in Denmark and compare the present situation with scenarios of more waste being recycled, incinerated or consigned to landfill. The investigations are made in accordance with ISO 14040-43 and based on the newly launched methodology of consequential LCA and following the recent guidelines of the European Centre on Waste and Material Flows. The LCA concerns the Danish consumption of paper in 1999, totalling 1.2 million tons. The results of the investigation indicate that the waste hierarchy is reliable; from an environmental point of view recycling of paper is better than incineration and landfilling. For incineration, the reason for the advantage of landfilling mainly comes from the substitution of fossil fuels, when incinerators provide heat and electricity. For recycling, the advantage is related to the saved wood resources, which can be used for generating energy from wood, i.e., from renewable fuel which does not contribute to global warming.     

Biological Integrity in Mid-Atlantic Coastal Plains Headwater Streams

The objective of this study was to assess the applicability of using landscape variables in conjunction with water quality and benthic data to efficiently estimate stream condition of select headwater streams in the Mid-Atlantic Coastal Plains. Eighty-two streams with riffle sites were selected from eight-two independent watersheds across the region for sampling and analyses. Clustering of the watersheds by landscape resulted in three distinct groups (forest, crop, and urban) which coincided with watersheds dominant land cover or use. We used non-parametric analyses to test differences in benthos and water chemistry between groups, and used regression analyses to evaluate responses of benthic communities to water chemistry within each of the landscape groups. We found that typical water chemistry measures associated with urban runoff such as specific conductance and dissolved chloride were significantly higher in the urban group. In the crop group, we found variables commonly associated with farming such as nutrients and pesticides significantly greater than in the other two groups. Regression analyses demonstrated that the numbers of tolerant and facultative macroinvertebrates increased significantly in forested watersheds with small shifts in pollutants, while in human use dominated watersheds the intolerant macroinvertebrates were more sensitive to shifts in chemicals present at lower concentrations. The results from this study suggest that landscape based clustering can be used to link upstream landscape characteristics, water chemistry and biotic integrity in order to assess stream condition and likely cause of degradation without the use of reference sites. Notice: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.     

Cyanotoxin management and human health risk mitigation in recreational waters

The occurrence and severity of harmful cyanobacterial or blue-green algal blooms (HABs) have increased in recent decades, posing a serious threat of illness to humans. In some countries, water contaminated with cyanotoxins that is used for drinking or haemodialysis has posed a particularly serious risk. However, it is now recognized that recreational exposure to natural toxins by skin contact, accidental swallowing of water or inhalation can also cause a wide range of acute or chronic illnesses. In this review, we focus on the importance of cyanotoxin management in recreational waters. The symptoms related with HAB poisonings, the recommended safety concentrations limit for cyanobacteria and cyanotoxins in such waters, as well as early health hazard indicators of their presence and their monitoring are all discussed. We also present in this review an overview of the methods developed in recent decades for eliminating cyanobacteria and the toxic compounds that they produce.     

Arctic terrestrial biodiversity status and trends: A synopsis of science supporting the CBMP State of Arctic Terrestrial Biodiversity Report

Ambio - This review provides a synopsis of the main findings of individual papers in the special issue Terrestrial Biodiversity in a Rapidly Changing Arctic. The special issue was developed to...